Special slow-bonding prestressed steel strand with excellent durability for two-section anchor cable and anchor rod
By using a two-stage slow-bonding prestressed steel strand design, combining rapid curing of the anchoring section with slow curing of the free section, the problems of insufficient durability and bearing capacity of prestressed anchor cables and anchor rods are solved, achieving the effect of high bearing capacity and full-length closure.
Patent Information
- Application Number
- CN202520736344.2
- Authority / Receiving Office
- CN · China
- Patent Type
- Utility models(China)
- Current Assignee / Owner
- Filing Date
- 2025-04-18
- Publication Date
- 2026-01-16
- Estimated Expiration
- 2035-04-18
AI Technical Summary
Existing prestressed anchor cables and anchor rods have poor durability and insufficient bearing capacity, making it difficult to simultaneously meet the requirements of high bearing capacity and full-length closure.
The design employs a two-section slow-setting prestressed steel strand. The anchoring section uses a slow-setting adhesive that cures quickly in a short period, while the free section uses a slow-setting adhesive with a conventional curing speed. This allows the anchoring section to cure quickly and bond with the grout, while the free section cures slowly in the later stages. The two sections are distinguished by the ribbed sheath.
It achieves high load-bearing capacity and full-length closure, with excellent durability. After the anchoring section is quickly cured, it can be stressed like a bonded steel strand, while the free section is slowly cured in the later stage to achieve full-length closure, significantly improving durability.
Smart Images
Figure CN223806168U_ABST
Abstract
Description
TECHNICAL FIELD
[0001] The utility model belongs to civil engineering technical field, concretely relates to a new two -segment type anchor cable anchor rod special slow -bonded prestressed steel strand with excellent durability. BACKGROUND
[0002] With the development of city, building develops more and more to underground space, subway station is often built in the place of underground 20-30 meters, the water buoyancy of the floor of these underground buildings is quite big, needs to adopt prestressed anchor rod to prevent the floor to float, and the underground powerhouse in water conservancy project also needs to adopt prestressed anchor cable to reinforce surrounding rock mass, to ensure the safety of underground powerhouse, the highway on both sides of the dangerous rock section also adopts prestressed anchor cable to reinforce, the design life of these projects is generally more than 100 years, requires the durability of prestressed anchor cable, anchor rod must satisfy the first class anticorrosion requirement, and requires anchor rod, anchor cable full length to be in closed environment.
[0003] At present, the steel strand of commonly used prestressed anchor cable, anchor rod has three kinds: bonded prestressed steel strand, unbonded prestressed steel strand and slow-bonded prestressed steel strand. Bonded prestressed anchor rod anchor cable refers to the anchoring section prestressed steel strand is completely bonded, gripped by surrounding concrete or cement paste. Unbonded prestressed anchor rod anchor cable refers to the anchoring section prestressed steel strand is free to stretch and deform, and does not bond with surrounding concrete or cement paste. The unbonded prestressed steel strand is coated with anticorrosive grease throughout the length, and is protected by a plastic tube. The anchoring section steel strand of slow-bonded prestressed anchor rod anchor cable can freely stretch and deform without bonding with surrounding slow-setting adhesive during the tensioning period after grouting in the anchor rod anchor cable hole, while the slow-bonded steel strand is bonded with surrounding grouting paste as the slow-setting adhesive around the prestressed steel strand gradually solidifies after the tensioning period.
[0004] The prestressed anchor cable and anchor rod using bonded steel strand can better exert the bonding force of the grouting paste in the anchoring section and the surrounding rock and soil, as the anchoring section steel strand is completely bonded with the grouting paste to form a whole, and there is no local pressure restriction of the anchoring section carrier, and the bearing capacity can reach 1000 tons. However, cracks will occur in the grouting paste in the anchoring section during the tensioning of the anchor cable and anchor rod, leading to corrosion of the steel strand. Moreover, after the grouting paste cracks, underground water will come into contact with the steel strand and enter the anchor clamp through the gap between the steel strands, leading to corrosion of the clamp. The durability of this type of anchor cable and anchor rod is difficult to meet the first class corrosion requirement. The advantages of this type of anchor cable and anchor rod are high bearing capacity and excellent economic indicators of bearing capacity hole length ratio, and the disadvantage is poor durability.
[0005] At present, the prestressed anchor cable or anchor rod using unbonded steel strand or slow-bonding steel strand has the following problems: the steel strand in anchoring section is not bonded with grouting body during tensioning, the bearing capacity is completely subject to the local pressure capacity between the anchoring end bearing body of anchoring section and grouting body, the bearing capacity of the anchoring section cannot fully utilize the bonding force between grouting body and surrounding rock, and the bearing capacity can only reach 100 tons at most. The anchor cable or anchor rod has the advantages of good durability and full-length closed steel strand, but has the disadvantage of poor economic index of bearing capacity-hole length ratio, and the bearing capacity is far less than that of bonded prestressed anchor cable or anchor rod under the same geological conditions and same hole diameter and depth. Content of the utility model
[0006] The utility model discloses a two-section slow-bonding steel strand with good durability, which can overcome the shortcomings of the existing anchor cable or anchor rod and has high bearing capacity and full-length closed anticorrosion requirement.
[0007] In order to achieve the above-mentioned purpose, the utility model provides a new two-section slow-bonding prestressed steel strand with good durability for anchor cable or anchor rod, which comprises a steel strand core, a sheath sleeved on the steel strand core and a slow-bonding layer between the steel strand core and the sheath. The slow-bonding layer comprises a first section (such as anchoring section) slow-bonding layer and a second section (such as free section) slow-bonding layer distributed along the longitudinal axis of the steel strand. The curing time of the first section slow-bonding layer is different from that of the second section slow-bonding layer.
[0008] As a preferred embodiment, the first section slow-bonding layer is located in the anchoring section of the slow-bonding prestressed steel strand, the second section slow-bonding layer is located in the free section of the slow-bonding prestressed steel strand, and the standard curing time of the first section slow-bonding layer is shorter than that of the second section slow-bonding layer.
[0009] As a preferred embodiment, the diameter of the steel strand core is 15-28 mm.
[0010] As a preferred embodiment, the sheath is a ribbed sheath.
[0011] As a preferred embodiment, the ribbed sheath has at least two protruding ribs.
[0012] As a preferred embodiment, the standard curing time of the first section slow-bonding layer is not more than 60 days.
[0013] As a preferred embodiment, the tensioning applicable period of the second section slow-bonding layer is not less than 60 days, and the standard curing time is at least 180 days.
[0014] In a preferred embodiment, the outer surface of the sheath is provided with a structure that distinguishes the first adhesive layer from the second adhesive layer.
[0015] In a preferred embodiment, the portion of the sheath corresponding to the first adhesive layer and the portion corresponding to the second adhesive layer may have the same or different shapes.
[0016] In a preferred embodiment, the length of the first section of the adhesive layer is at least 1.5 meters.
[0017] In a preferred embodiment, the length ratio of the first section of the soft-adhesive layer to the second section of the soft-adhesive layer is at least 1:3.
[0018] The slow-setting bonded steel strand of this utility model is a two-section design. The anchoring section of the anchor cable or anchor rod is coated with a slow-setting adhesive that cures quickly in a short period of time (e.g., standard curing time within 60 days). The free section is coated with a slow-setting adhesive with a conventional curing speed (e.g., tensioning application period of 90 days, standard curing time of more than 270 days). After grouting the duct, the anchoring section of the anchor cable or anchor rod using this two-section slow-setting bonded steel strand can bear the same force as the bonded steel strand anchor cable or anchor rod, and its bearing capacity is the same as that of the bonded steel strand anchor cable or anchor rod. Moreover, it can achieve full-length closure and has excellent durability. Attached Figure Description
[0019] Figure 1 This is a schematic diagram of the structure of the two-section anchor cable and anchor rod special slow-bonding prestressed steel strand of this utility model.
[0020] Figure 2 For the anchorage section of the two-ribbed, two-segment, loosely bonded prestressed steel strand along Figure 1 A schematic diagram of the AA cross-section.
[0021] Figure 3 For the four-rib, two-section, slow-bonding prestressed steel strand anchorage section along Figure 1 A schematic diagram of the AA cross-section.
[0022] Figure 4 For the anchorage section of the three-rib, two-section, slow-bonding prestressed steel strand... Figure 1 A schematic diagram of the AA cross-section.
[0023] Figure 5 For the free section of the two-ribbed, two-segment, loosely bonded prestressed steel strand Figure 1 A schematic diagram of the BB cross-section.
[0024] Figure 6 For the free section of the four-rib, two-section, loosely bonded prestressed steel strand... Figure 1 A schematic diagram of the BB cross-section.
[0025] Figure 7 The free section of the two-section type slow-bonding prestressed steel strand for anchor cable anchor rod is along Figure 1 The B-B section view of the two-section type slow-bonding prestressed steel strand for anchor cable anchor rod is shown.
[0026] Figure 8 The enlarged view of the C part of the two-section type slow-bonding prestressed steel strand for anchor cable anchor rod is shown. Figure 1
[0027] Figure 9 The schematic view of the two-section type slow-bonding prestressed steel strand for anchor cable anchor rod applied to anchor cable anchor rod engineering is shown.
[0028] The reference signs are as follows:
[0029] 1 - the anchoring section of the two-section type slow-bonding prestressed steel strand for anchor cable anchor rod
[0030] 2 - the free section of the two-section type slow-bonding prestressed steel strand for anchor cable anchor rod
[0031] 3 - the steel strand core
[0032] 4 - the first slow-bonding layer
[0033] 5 - the sheath
[0034] 6 - the second slow-bonding layer
[0035] 7 - the anchor rod anchoring section
[0036] 8 - the anchor rod free section
[0037] 9 - the grouting body of the anchor rod anchoring section and the two-section type slow-bonding prestressed steel strand anchoring section combination
[0038] 10 - the grouting body of the anchor rod free section and the two-section type slow-bonding prestressed steel strand free section combination
[0039] 11 - the two-section type slow-bonding prestressed steel strand for anchor cable anchor rod
[0040] 12 - the anchor device
[0041] 13 - the anchor pad
[0042] 14 - the anchor sealing concrete
[0043] 15 - the protected structure DETAILED DESCRIPTION
[0044] The utility model will be further described below in combination with specific embodiments. It should be understood that the following embodiments are only used to illustrate the utility model, and are not used to limit the scope of the utility model.
[0045] The two-section type anchor cable anchor rod special slow-bonding prestressed steel strand is made of existing material products, and can be obtained through commercial channels.
[0046] The slow-bonding prestressed steel strand is a prestressed steel strand coated with a slow-bonding special adhesive and a high-density polyethylene sheath according to the standard JG / T 369-2012 Slow-bonding prestressed steel strand.
[0047] The slow-bonding adhesive is a cementing material coated on the prestressed steel strand outside the sheath and solidified at an expected time according to the standard JG / T 370-2012 Slow-bonding prestressed steel strand special adhesive, and is referred to as a slow-bonding adhesive.
[0048] The solidification time refers to the time of the slow-bonding adhesive from preparation to solidification to reach a specified strength. The solidification time at room temperature (25℃) is referred to as a standard solidification time. For example, a slow-bonding adhesive with a standard tensioning application period of 90 days and a standard solidification time of 270 days is marked as Ra-90-270-JG / T 370. Various commercial slow-bonding adhesives with different solidification times (for example, a solidification time of 60 days, 90 days, 120 days, 180 days, 270 days, 360 days, 720 days, etc.) are available in the prior art.
[0049] The slow-bonding layer is formed by the slow-bonding adhesive.
[0050] As shown in Figures 1 to 8 The two-section type anchor cable anchor rod special slow-bonding prestressed steel strand includes a steel strand core body 3, a sheath 5 sleeved outside the steel strand core body 3, and a slow-bonding layer between the steel strand core body 3 and the sheath 5. The slow-bonding layer includes a first section slow-bonding layer 4 and a second section slow-bonding layer 6 distributed along the longitudinal axis direction of the steel strand, and the solidification time of the first section slow-bonding layer 4 is different from the solidification time of the second section slow-bonding layer 6.
[0051] Preferably, the first section slow-bonding layer 4 is located at the anchoring section 1 of the two-section type anchor cable anchor rod special slow-bonding prestressed steel strand, the second section slow-bonding layer 6 is located at the free section 2 of the two-section type anchor cable anchor rod special slow-bonding prestressed steel strand, and the solidification time of the first section slow-bonding layer 4 is shorter than the solidification time of the second section slow-bonding layer 6.
[0052] More preferably, the standard solidification time of the first section slow-bonding layer is less than 60 days, and the tensioning application period of the second section slow-bonding layer is not less than 60 days, and the standard solidification time is at least 180 days.
[0053] Preferably, the diameter of the steel strand core is 15 to 28 mm, for example 15.2 to 27.8 mm. For example, the two-section type slow-bonding prestressed steel strand of the utility model is coated with a layer of slow-setting adhesive outside the ordinary nominal diameter 15.2, 17.8, 21.8 and 27.8 mm steel strand, and a layer of ribbed sheath outside the slow-setting adhesive.
[0054] Preferably, the sheath 5 is a ribbed sheath. More preferably, the ribbed sheath has at least two protruding ribs. For example, the ribbed sheath can adopt a two-rib, three-rib, four-rib or five-rib shape. The sheath 5 can be a ribbed high-density polyethylene sheath.
[0055] Preferably, the outer surface of the sheath is provided with a structure for distinguishing the first section slow-bonding layer from the second section slow-bonding layer. For example, the structure can be a sheath coated with different colors or different shapes. The pattern or shape observed on the outer surface of the sheath can facilitate the distinction between the slow-bonding steel strand with fast curing of the anchoring section and the slow-bonding steel strand with normal curing of the free section. For example, the part of the sheath 5 corresponding to the first section bonding layer 4 can be different in shape from the part corresponding to the second section bonding layer 6, or can be made in the same shape but different colors.
[0056] Figure 9 A schematic diagram showing the application of the two-section type slow-bonding prestressed steel strand for anchor cable and anchor rod in anchor cable and anchor rod engineering is shown. The following will be described taking anchor rod as an example, but the structure is also applicable to anchor cable. As shown in the figure, in anchor rod engineering, the anchor rod includes an anchor rod anchoring section 7 and an anchor rod free section 8, the anchoring section of the two-section type slow-bonding prestressed steel strand for anchor cable and anchor rod 11 corresponds to the anchor rod anchoring section 7, the free section of the two-section type slow-bonding prestressed steel strand for anchor cable and anchor rod 11 corresponds to the anchor rod free section 8, after grouting, the anchor rod anchoring section grouting body and the two-section type slow-bonding prestressed steel strand anchoring section combination 9 and the anchor rod free section grouting body and the two-section type slow-bonding prestressed steel strand free section combination 10 are formed. The free section of the two-section type slow-bonding prestressed steel strand bundle 11 passes through the protected structure 15, connects the anchor pad 13 and the anchor device 12, and after tensioning and locking, the anchor sealing concrete 14 is filled to realize the fixation and protection of the structure. The slow-bonding steel strand of the utility model is two-section type, after the grouting of the anchor cable and anchor rod in the hole, the anchoring section can be stressed like the bonded steel strand anchor cable and anchor rod, the bearing capacity is the same as that of the bonded steel strand anchor cable and anchor rod, and the free section can be slowly solidified in the later period, thereby realizing the time period and stage anchoring of the anchor rod and anchor cable, and also realizing the full-length closure of the anchor rod and anchor cable, and the durability is very excellent.
Claims
1. A two-stage slow-bonding prestressed steel strand for an anchor cable anchor rod with excellent durability, the slow-bonding prestressed steel strand comprising a steel strand core, a sheath covering the steel strand core, and a slow-bonding layer between the steel strand core and the sheath, characterized in that, The slow-bonding layer comprises a first slow-bonding layer and a second slow-bonding layer distributed along the longitudinal axis of the steel strand, the standard curing time of the first slow-bonding layer being different from that of the second slow-bonding layer. 2. The two-stage, non-shrinkage-cured, prestressed, special strand for rock bolting and anchoring according to claim 1, characterized in that, The first slow-bonding layer is located at the anchoring section of the slow-bonding prestressed steel strand, and the second slow-bonding layer is located at the free section of the slow-bonding prestressed steel strand, and the standard curing time of the first slow-bonding layer is shorter than that of the second slow-bonding layer.
3. The two-stage, non-shrinkage-cured, prestressed, special strand for rock bolting and anchoring according to claim 1, characterized in that, The diameter of the steel strand core is 15-28 mm.
4. The two-section anchor cable and anchor bolt special slow-bonding prestressed steel strand according to claim 1, characterized in that, The sheath is a ribbed sheath.
5. The two-stage, non-shrinkage-cured, prestressed, special strand for rock bolting and anchoring according to claim 4, characterized in that, The ribbed sheath has at least two protruding ribs.
6. The two-section anchor cable and anchor bolt special slow-bonding prestressed steel strand according to claim 1, characterized in that, The standard curing time of the first slow-bonding layer is not more than 60 days.
7. The two-section anchor cable and anchor bolt special slow-bonding prestressed steel strand according to claim 1, characterized in that, The second slow-bonding layer has a tensioning applicable period of not less than 60 days, and a standard curing time of at least 180 days.
8. The two-section anchor cable and anchor bolt special slow-bonding prestressed steel strand according to claim 1, characterized in that, The outer surface of the sheath is provided with a structure distinguishing the first slow-bonding layer from the second slow-bonding layer.
9. The two-section anchor cable and anchor bolt special slow-bonding prestressed steel strand according to claim 1, characterized in that, The portion of the sheath corresponding to the first slow-bonding layer and the portion corresponding to the second slow-bonding layer are different in shape or the same.